Electrical communication system



May 21, 1940.. H. F. ELLIOTT ELECTRICAL COMMUNICATION SYSTEM Filed May29, 1936 8 Sheets-Sheet l INVENTOR.

H r ld FEM/oft 71 2 W ATTORNEY.

May 21, 1940. H. F. ELLIOTT 2,201,162

ELECTRICAL COMMUNICATION SYSTEM Filed May 29, 1936 8 Sheets-Sheet 2INVENTOR Harolcl F Elliott May 21, 1940.

H. F. ELLIOTT ELECTRICAL COMMUNICATION SYSTEM Filed May 29, 1936 8Sheets-Sheet 3 e Illlllllllllllllllllill 4 llllllllllllllllli jllllllllllllllllllfll j INVENTOR Harold FI Ell/bit y 21, 1940- H. F.ELLIOTT 2,201,162

ELECTRICAL COMMUNICATION SYSTEM Filed May 29, 1936 8 SheetsSheec 4AAAAAA AAAAAAA INVENTOR Harold F Elliott May 21, 1940 HRELUOTT ,201,16

ELECTRICAL COMMUNICATI 0N SYSTEM Filed May 29. 1936 8 Sheets-Sheet 5 l Ht "W 1 M I ;E I m fill v 2:: 42 mrl g INVENTOR.

A ORNEY.

Filed May 29, 1936 8 Sheets-Sheet 6 I'NVENTOR glam/a HEN/ail ATT RNE

May 21, 1940. H. F. ELLIOTT ELECTRICAL COMMUNICATION SYSTEM Filed ma29,1936

8 Sheets-Sheet 7 I INVENTOR I BY Harold [EH/ a May 21, 1940. H, F.ELLIOTT 1 ELECTRICAL COMMUNIGATION SYSTEM Filed May 29, 19568-Sheets-Sheet 8 INVENTOR {Ham/1 BY I F I MORNE r l l I I I I I I I I II I I I I l I l I I I I I I I I I I I l l l I I I I I I I I I I IPatented May 21, 1946 UNITED STATES tATENT OFFICE Application May 29,

4 Claims.

The inventions described in this application and in my pendingapplication Serial No. 82,495 filed May 29, 1936, pertain to Electricalcommunications and multiple function control clocks. The methods andapparatus described and claimed in these applications are not limited tothe usages chosen for illustration but are useful in a wide variety offields as will be evident to those skilled in mechanical and electricalarts.

For the purpose of illustrating principles and methods I have chosen fordescription herein electrical communications and receiving systems suchas may be used for receiving intelligence by wire or radio in the formof speech, vision, facsimile or other signaling methods. It will beunderstood that I do not limit myself to the examples or applicationschosen for illustration, but claim broadly the inventions set forth inthe claims of this and the aforesaid copending application. As appliedto receivers for home entertainment, my system has the advantages ofpermitting scheduled programs to be received auto matically atpredetermined hours by simple presetting means. It also has the furtheradvantage of using precisely pre-tuned circuits which relieve theoperator of the tuning operation required in existing methods. Thepretuned circuits assure improved quality of reception since errors intuning resulting from carelessness or lack of operative skill areavoided. Each of the selected channels may be pretuned for optimumresults commensurate with the prevailing conditions. For example: adistant station may have sharp tuning for selectivity while a nearbystation may have broad band-pass tuning for improved quality. Thevarious channels may be adapted to varied purposes, for example; theremay be provided several channels for reception over wires, severalothers for long wave radio, others for short wave radio, television orfacsimile. Other settings may provide for the operation of householdappliances, lighting the furnace, ringing a bell, turning on apercolater or regulating an even by a schedule. possibilities can bestbe grasped by referring to the attached drawings showing severalpreferred forms and illustrative examples of applications.

Referring to the accompanying drawings in which like numerals ofreference indicate similar parts throughout the several views;

Figure 1 shows in outline the circuits of an electrical communicationreceiving set embodying the methods, apparatus and principles of myinventions; Figures 2 and 3 show an elevation, and details of thereceiver of Fig. 1; Fig- The many advantages and 1936, Serial No. 82,494

ures 4 and 5 show an alternative arrangement of details; Figure 6 showsa partial view and certain' details of another receiver suitable for usewith my system; Figures 7-12 inclusive show partial sections andelevation of the same; Figures l3 and 14 show partial assemblies andsections of still another receiver. Figs. 15-19 show modifications ofthe system shown in Fig. 1.

Radio and wire line receiving circuits may be applied to any of theseassemblies and the type of circuit may be any suitable to the purpose.Examples of circuits involving both superheterodyne and tuned radiofrequency methods for radio, wire line, voice or other reception areillustrated in the circuit diagrams of which Figure 1 shows a tunedradio frequency receiving circuit embodying the principles and methodsof my inventions, and Fig. 15 which, for lack of space, is continued inFig. 16, shows circuits combining the two so that the advantages of eachare obtained. Figure l and Figure 17 show two relay control circuitsutilizing two methods of control; Figure 18 shows an application of mysystem to a receiver having motor operated controls; Figure 19illustrates a timing and control system having several stations.

In the specific embodiments of the invention illustrated in saiddrawings, reference will be made initially to Figure 1, wherein isshown, in diagrammatic form, the controls and circuits of a radioreceiver embodying my system and utilizing the multiple function controlclock described in my copending application Serial No. 82,495 filed May29, 1936, to which reference is made for constructional details thereof.This is one of the important fields of application of this clock and hasbeen chosen here as an example to illustrate one method of its use.Briefly the system of Figure 1 comprises a radio receiver having a relaycontrolled channel selecting system arranged for automatic operationunder clock control and also for manual operation under push buttoncontrol. Numerals l to II inclusive indicate diagrammatically aplurality of station or channel busses, while one of a plurality of timebusses is indicated by numeral I2. The busses of each set are preferablyparallel, and one set is perpendicular to the other, but without directcontact, thus giving the crisscross appearance of the busses of the twosets. Interconnection between any one bus of one set with any one bus ofthe other set may be accomplished by an interconnector such as isindicated at l3. There are as many interconnectors as there are bussesin one set, that is, the

nun'lber of busses in the set of busses upon which the interconnectorsare slidable determines the number of interconnectors provided.Diagrammatically indicated at M and iii are control means by which theinterconnectors may be moved individually to selected interconnectingpositions by members it and 51. Control means 55 comprises a fingerindex dial somewhat like "do dial of an automatic telephone. In thenormal or unset position the interconnectors l3 are all slid to a placewhere they will overlie bus 2 i, which as shown but not necessarily, isa neutral or inactive bus merely affording a position of rest for theinterconnectors. As between the time busses such as if. on which theinterconnectors slide and members I l, Eli, i6 and I! which actuate theinterconnectors, there is a relative movement. Member ll may be movedlongitudinally of itself by means of time dial l4 and member it and thusprojection 13 upon member i! may be brought opposite any one of theinterconnectors, or, conversely said member may be longitudinallystationary and the bank or set of time busses may be moved laterally toobtain the relative positioning with any one bus opposite theprojection. After projection 58 is poysitioned opposite the selectedinterconnector, member it is moved transversely of itself andIongitudinally of the set of time busses, sliding interconnect-or l3down to the desired cross bus of the other set such as station bus 3illustrated. As stated, member M is a time index dial which servesthrough control means [9 to move projection it; to a selected time bus.The finger index dial l5 then serves by clockwise rotation to move theinterconnector, as l3, associated with that time bus to a Selectedstation bus, as 3. Member 2t, actuated through mem her it bycounterclockwise rotation of dial l5 serves to return allinterconnectors to neutral bus l i. Reference is made to myaforementioned copending application Serial No. 82,495/ filed May 29,193d, for mechanical arrangement and constructional details of theseparts. As set forth in detail therein, time dial i4 preferably takes theform of a rotatable ring having ninetynotches, one for each quarter hourof the twenty-four hours of a day. This ring is preferably indexed orgraduated in quarter hour intervals. Member i! is preferably a ring ofinsulating material having a projection I8 arranged to engage anyindividual interconnector, as [3. Rotation of dial it rotates ring llthrough the medium of a pin or other linkage l9, thus bringingprojection it opposite any selected interconnector. When projection l8has been positioned opposite the interconnector corresponding to theselected quarter hour, this interconnector may then be moved to thedesired station bus, as by rotation of dial l5. This is preferablybrought about through the medium of a cam or lead screw, or othersuitable linkage diagrammatically shown at it in Fig. 1. This linkageserves to translate rotary motion of dial l5 into transverse motion ofring ll, and projection it. As set forth in detail in my co-pendingapplication S. N. 82,495, filed May 29, 1936, the time busses, as 22,preferably take the form of a series of rods arranged in cylindricalformation around the axis of dials i l and 15, parallel with this axis,while the station busses, l to H, preferably take the form of a set ofconducting rings concentric with the same axis, which is also the axisof ring ll. Member is preferably a second insulating ring having thesame axis, and arranged so that reverse rotation of dial I5 causeslinkage IE to move ring 20 along its axis, engaging all interconnectorsand returning all to neutral bus I l.

The receiver shown in Figure 1 is of the tuned radio frequency type,having two radio frequency amplifier stages 2! and succeeded by agovernor 2324, a compensator and volume control stage 25, a demodulator25, an audio frequency amplifier 2'1 with phase .reverser 2B and feedingpower output tubes 29 and 3E). The input to the first stage 2! includesan input transformer 3|, which is tuned to select desired programchannels by adjustable capacitors 32-33- 34 etc. which are connectedinto the circuit by relay contacts 35, 36, 37, etc. of which relaycontact 36 is shown actuated into circuit closing position. The inputcircuits of stages 22, and demodulator 26 are similarly arranged withadjustable capacitors and relay contacts, identified by similarreference numerals but with the addition of exponents. Relay contacts 36and the corresponding contacts identified by numeral 36 with exponentsin succeeding stages are closed in unison by a relay armature, shown at38, through the medium of a common control member 38A (indicated bydotted line in Figure 1). Once closed, the associated group of contactsare held closed by a latch, or interlock 39. Suitable mechanism forthese parts will be described more in detail in several formshereinafter. A trip mechanism, indicated at i-i, opens previouslylatched relays whenever a shift is made from one channel to another andalso whenever an off signal is given by the clock or by the push buttonswhich are indicated at 4|. In Figure l, the relay contacts associatedwith channel 2 are shown closed, tuning all circuits for this channel.Channel I is indicated as a variable channel whose tuning may be changedto receive a range of radio stations by turning dial e2. Channels 2, 3,et sequel through 9, illustrate channels having tuning means which arepre-adjusted and then left fixed for the reception of definite stations.Additional channels are omitted for sake of simplicity in the circuitdiagram, but may be similar to those shown or take other suitable form.It will be obvious that the relays may be arranged in a great variety ofways to serve many purposes. For example, one variable and three fixedchannels may be provided for reception of radio broadcast programs,three other channels may be provided for reception of programs over wirelines at audio or carrier frequency, another may provide for television,another for facsimile or news service and so on for as many channels asdesired to include in the apparatus. Each channel may have theconstruction and response characteristics best suited to the purposethereof. The relays may also be used to control the household furnace,range or other appliances.

In the arrangement illustrated in Figure 1, the control impulses whichoperate the various relays are of short duration and are routed fromsource through bus 48, clock contact arms 46 and 47 to the time busses,as 52, thence through the interconnectors, as 13, to the station bus, as3, contacted by said interconnector, thence to the relay operatingcoils, as l3, and trip coil 44 back to the source of control current4'5. This source is indicated at as comprising a step down transformer,copper oxide rectifier and storage capacitor. The relays may also beoperated manually by the push buttons indicated at 4|. In thearrangement shown in Figure 1, contact arm 46 is driven with the minutehand of the clock and makes a contact of brief duration at 15 minuteintervals with bus 48. Arm 4'! is driven with the hour hand anddistributes the impulse from arm '36 to the time bus, as l2,corresponding to the particular 15 minute interval. The interconnectors,as it, may be set for any desired schedule of programs, or otherfunctions by use of the time index and station dials shown schematicallyat I i and E to which reference has been made. As described in detail inmy copending application it is only necessary to set time index is atthe desired quarter hour and then to dial the desired station on dialii: in order to make the interconnection necessary to bring in thatstation at that time. With a 24 hour clock and 96 time busses arrangedat quar ter hour intervals, a change of programs may be had every 15minutes if desired. In the arrangement of busses shown in Figure 1,station bus I, is an off bus and serves to energize the trip coil 44whenever it is desired to turn the receiver off either by the clock orby the push buttons.

Rheostats for volume and tone control are shown at 49 and 5B. A set ofcontacts indicated at 5|, operated in conjunction with the tuning relaycontacts, as 36, 36', etc. as indicated by common control 38A, serves toclose contactor 52 and energizes the power supply circuits whenever anyof the program relays are closed. Signal lamps, as indicated at 53, maybe included to show which channel is in operation if desired. Interlockcontacts 54'. may be operated in conjunction with the power relay foropening the circuit of the off bus, i, if desired. This refinementprevents the trip relay 4t from clicking in case the clock passes offimpulses when the set has already been turned off. A further refinementwhich may be desirable in some cases comprises a set of interlockcontacts introduced in series with the relay closing coils, such as 43,as indicated by crosses, as at 55. As described hereinafter inconnection with Figures 2 and 7 these contacts are preferably arrangedto open after the associated relay has been latched closed, therebyopening the operating circuit of that relay. This refinement preventsthe relay drawing current or clicking after it has been closed.

In order to cushion surges in the amplifier and speakers when a shift ofchannels is made, a set of interlock contacts, as indicated at 56, isprovided. These contacts cause the automatic gain control bus to receivea negative charge from rectifier 57 whenever any of the relays are inprocess of opening or closing. The gain of stages 2|, 22 and 25 is thusmomentarily reduced causing one station to fade out and the other tofade in. As described in greater detail hereinafter in connection withFigures 2, 4 and 7, the construction of fading relay contacts, as 56, issuch that a circuit is momentarily closed from bus 56A to 56B wheneverany of the channel selecting relays is in the process of opening orclosing.

It will be obvious that a great variety of means may be conceived forcarrying out the various functions illustrated and described above. Whenused with the multiple function control clock described in my copendingapplication Serial No. 82,495 filed May 29, 1936, to which reference hasbeen made, a receiver possessing many highly desirable features isobtained. Broadcasting, although a relatively new art, has alreadysettled quite definitely into schedules and channels. By means of thetime and station dials any desired schedule of programs may be set upfor the succeeding 24 hour period. Alternative selections may be madevia the push button controls at any time, the push button beingeffective only for the one period then in progress and the clockresuming control whenever a previously set schedule is encountered asthe clock rotates. The use of relays operated by impulses of shortduration and held by mechanical interlocks has several advantages. Theclock and push button controls may be connected directly in parallelwithout interference and the relay coils may be designed forintermittent service. Additional control units as described inconnection with Fig. 19 may readily be provided if desired.

Several methods of arranging the receiving circuit, relays, tuningcapacitors, coils and other elements for use with circuits of the typeshown in Figures 1, l5 and 16 will now be described.

Referring to Figure 2 the receiver here illustrated includes a pluralityof shield cans as 58 housing electrical circuit tuning apparatus, aplurality of switches of which 59, 60, BI and 62 are examples, aplurality of relay mechanisms for operating the switches of which 63, 64and 65 are examples. A suitable base plate, electronic tubes,transformers, capacitors, inductors and the like are of course providedbut will not be enumerated in detail here for the sake of simplicity.The arrangement of tubes, tuning apparatus, switches and relays is suchthat each amplifier stage may be connected with any one ofa plurality ofcircuit tuning elements by the action of the relays. The relays are inturn arranged so that the operation of any one relay brings into actiona coordinated set of circuit elements specifically adapted to thepurpose to which the relay is devoted, as for example an entertainmentprogram via a wire line, or via radio, or a television program via shortwave radio.

In the arrangement shown in Figure 2 each relay comprises a rotaryshaft, as 66, carrying rotary switches as 67 and 68, operated byelectromagnets such as are shown at 69 and armatures such as and H. Thearmature is shown in open position at 10 and in closed position at H,being held closed by latch 12. Each amplifier stage may be provided withone or more busses as 13, through which connections may be made to thetuning elements associated with that stage, via the switches. The bussesand switches for each stage may be grouped in suitable shieldedcompartments as indicated at 13A. The shaft of each relay, as 86, maycarry as many sets of contacts as required to perform the switchingoperations necessary to connect and tune the channel associated withthat relay. The contacts may be constructed in a great variety of waysdepending upon the service to be performed, production methods, etc. Thearrangements shown at 59 and 60 provide double break connections fromthe bus 13 to the tuning elements such as are shown in shield 58. Theswitches, busses and tuning elements are thus completely isolated whenthe switches are open, avoiding capacity effects and interactionsbetween circuits. A switch such as is shown at 62 may be used where asingle break with nominal stray capacity coupling is satisfactory. Theswitch shown at 6| provides for momentary connections between busses 83and 84 in the fader circuit discussed further below.

The relay arrangement shown in Figure 2 includes a mechanicalinterlocking system which provides for holding the relays closed afterthey have been set by electrical impulses of short duration, When theoperating coils of any relay are energized the switches attached to thatrelay are closed and locked and all other relays are openedautomatically. This is arranged by providing each relay with a latch, asillustrated at I2 for relay 64 which is shown closed, and at 2B forrelay 65 which is shown open. Release relay l4 is mechanically connectedwith the latches of all relays through release bar 1. A trip mechanism16 interconnects release relay M and release bar 15 in such a way thatan impulse to relay 14 moves the bar E5 to the left thereby tripping allrelay latches and then immediately permits bar 15 to return to itsoriginal position. The release relay M comprises two electromagnets 14Aand MB and an armature MC which pivoted to rotate on pin MD. A trip armME is attached to the armature and rotates with it about pin MD as anaxis. Spring MP holds the rotating elements in the position illustratedagainst the stop MG when the magnets are not energized. When current isapplied to electromagnets MA and MB armature 74C rotates clock-- wise,carrying with it trip arm ME. The outer end of the trip arm ME engageswith latch to which is attached to the bar it: through the pivot 76A.Bar '15 is pulled to the left, as viewed in Fig. 2, by the rotation ofthe trip arm ME about the pivot MD. The outer end of the trip arm 14Eswings in an arc about the pivot W-D as shown by the dotted line H. Dueto this curvature, after a few degrees of rotation. the outer tip of armME. slides from the outer tip of latch 16 to disengage the two members.Spring i lii then pulls bar 15 to the right against the stop 15A. Bar 15may slide in grooves or may be suspended on rotatable arms as 153. Whenthe magnets MA and MB are tie-energized, spring 14F pulls trip arm 14Eback to the position illustrated in Fig. 2. Latch arm I5 which ispivoted to bar 15 at 16A is pushed out of the way by the tip of arm MEas it passes. After this the spring 16B pulls the latch l6 back againstthe stop 16C to the position illustrated in Fig. 2 and trip arm l lE andthe latch 56 are in position for another cycle of operation. Thispermits any main relay, as 64, simultaneously or thereafter energized,to be latched shut as shown accomplished withrespect to latch 12. Anyrelay not energized will be left open, as is the case with respect torelay 65. It is thus possible to set any relay, and release anypreviously set relay by a single impulse of short duration. To this end,the operating coils of the release relay T l may be connected in areturn circuit common to the operating coils of all relays shown at itin Figure 1. Release relay 'M then operates whenever any of the settingrelays are actuated. All relays may be opened by routing an impulsethrough the coils of release relay l4, separately. In the circuits ofFigure 1, bus 5 is allocated to this service, being an oil bus.

The circuit tuning elements may be of any type suitable to the functionto be performed. In some instances each tube may have a single tuninginductor and a plurality of adjustable tuning capacitors which may beconnected succestively to the inductor by the relays for tuning invarious channels or stations. This is the arrangement indicated inFigure 1. In other instances a plurality of tunable circuits, eachcornplete in itself, may be provided. The circuits pair of circuitsembodying features disclosed and claimed therein is illustrated in thepresent disclosure as the circuit tuning means within the shield cans at58 in Figure 2. Inductors ll and 18 are movable relative to one anotherand relative to damping ring 79 by means of knob 80. Each inductor hasits adjustable tuning capacitor illustrated at ill and 82. Oth r methodsdiscussed in this application may also be applied; for example band passaction may be obtained in any set of circuits by staggering the tuningof the element comprising the amplifier stages thereof, introducingdamping if required by use or" either fixed or variable resistors,either in series or in shunt with tuning elements. Examples of this arediscussed further in connection with the circuit diagrams, Figures 16and 15.

A switch suitable for operating the fading" or biasing arrangementindicated at in Figure 1 is shown at 6! in Figure 2. Busses 8 3 and 34(Figure 2) are momentarily connected together whenever the shaft isrotated either to open or close the switches thereon. This accomplishedby proportioning the switch elements; so that switch contact (HA (Fig.2) closes before contact 3513 opens, and vice versa,

Figure 3 shows a cut away plan view of the switches of the typedescribed in connection with Figure 2, like numerals of referenceindicating like parts.

Figures 4 and 5 show an alternative arm-agement for switches and tuningapparatus adapted for use with circuits and relays of the type shown inFigures 1 and 2. oi switches in closed and open position ar shown at andEach switch has its associated. adjustable tuning capacitors,illustrated at iii and 853. A flexible bus as 89, connects each group ofswitches with its associated inductor system, outlined at 93 analcorresponding amplifier tube, as illustrated. Suitable shieldedcompartments, as 9! and 212 are provided for the busses and tu ingelements asso ciated with. each amplifier To reduce manufacturing costs,associated tuning elements, as capacitors 8i and 88 may be assembled ingroups on a suitable base, as 93. The stud carrying th adjusting nut ofthe capacitor may extend to form one of the switch, as shown at 94, (seeFigure 5). Each relay may be provided with switches for energizing thepower supply system of the receiver either directly or through a powerrelay, as indicated at in Figure 1. Each relay may also carry a switchor switches for cutting oil the speakers, or for reducing the output orgain during switching operations in order to avoid objectionable noisesor other disturbances due to switching. An example of one suitable formof switch for purpose shown at 95 which is proper-tic ed so thatcontacts 95A close before contacts open, and vice versa, thus energizinga fading" or closing circuit as illustrated at :35 in Figure 1.

For circuit arrangements wherein it is desired to open the controlcircuit 0.? a given relay after it has been closed and latched,interlock contacts associated with the latches, as indicated at 95 and8! in Figure 2 may be used. Such contacts are useful when the clock orpush button mechanism is such that the control circuit is continuallyenergized. Such contacts may also be inserted in series in the controlcircuit as indicated at in Figure 1 to avoid clicking when an impulse issent to a relay already closed.

The tuning elements and relays of a radio receiver especially wellsuited to circuits of the type discussed in connection with Figures 1,l5 and 16 are shown in Figure 6 and associated partial elevational andsectional views '7 to 12 inclusive. Numerals 98 and 99 (Figure 6)indicate two of a plurality of relays which are used for making theconnections necessary to tune the receiver for various channels orstations. Four banks of adjustable tuning capacitors are indicated atHill to I03 inclusive. Each relay as 99 comprises an electromagnet, asshown at M Figure '7, and an armature, I05, which serve to operate aplurality of contacts through the medium of an insulating tie bar, seeI96 in Figure '7. This figure is a section along line l-l of Figure 6taken so as to show in elevation the operating mechanism and contacts ofrelay 99, which is shown here in closed position. Four sets of contacts,till, I08, I09 and H8 are provided for connecting into tuned circuitsthe tuning capacitors as Iflll, Ilil, Hi2 and IE3, associated with thechannel or station assigned to this particular relay. The trans formersof the amplifier stages whose circuits are thus tuned may be housed insuitable shields as indicated at i I l, Figure 6, and a bank ofamplifier tubes may be placed adjacent thereto as indicated at H2. Theswitches and capacitors associated with each stage may be housed in ashielded compartment as indicated at H3, Figures 6 and 7. A stationaryinsulating bar i M, Figures 6 and '7, may be provided for holding thestationary contacts in the required positions, cooperating with theinsulated tie rod, Hi6, Figures 6 and 7, which serves for actuating themoving contacts of the several switches. Further details of thesecontacts, rods. and bars are shown in Figure 12 representing aperspective view of contacts H0 and associated tie rod I96 and bar IM.

Each switch, as Hll, (Figs. 6, 7, and 12), comprises two spring leavesas l MA and HllB which carry contacts as Hill) and IHJD. Spring leafHilA is dovetailed into the insulating tie rod H36 as illustrated at iME in Fig, 12. Spring leaf HlA therefore moves with rod I86 whenever thelatter is actuated by armature 195 (Fig. 7). Armature I H5 is pivoted atHlliA. Energization of the electromagnet Iil l attracts armature N35 tothe magnet and shifts the bar M5 to the left as shown in Fig. 7. Thismoves all of the switch leaves IIBA which are dovetailed to the bar 596to the left and closes all of the associated contacts as H86 and Hill)thereby connecting into the circuit the tuning elements controlled bythese switches. Latch H8 engages the armature I85 and holds the switchesclosed after the magnet is de-energized When the latch H8- is tipped, as

* described hereinafter, the spring leaves IIBA of the switches pull tiebar N38 to the right until the armature Hi5 rests against the stopH3513. In order that this motion may open the contacts as H06 and Hill),spring leaf N63 is provided with a projection 5 ml" which engages with afixed stop H413. This stop is formed by a notch IHIA in the stationaryinsulating bar H4 (Fig. 12). Leaf HiiB is free to move to the left whenleaf 1 WA moves to the left for bringing contacts I WC and HOD intoclosed position. When leaf IIDA moves to the right, the motion of leafHUB is limited by the projection BIDF engaging the stop II IB. The notchIHIA thus positions leaf H813 so that motion of the tie bar I586 mayopen and close contacts H00 and HOD. The pressure applied to thecontacts is determined by the tension of the spring leaf KB, and thispressure is applied to the contacts the moment they are closed, beingapproximately the same as the pressure exerted by spring leaf HilBagainst stop (MB. The notched bar HA therefore serves to determine theposition of its associated spring leaves as HUB, and the constructionpermits definite contact pressures to be maintained as well as definitepositions. The construction also permits the moving switch elements asspring leaf HOA to serve as the spring for actuating armature m5 pullingit away from the magnet Hi4 when ole-energized. The dovetail and notchconstruction of insulating bars Its and I! permits the use of low coststampiugs and this construction likewise facilitates the assembly of themultiple switch parts.

In addition to the switches for performing tuning operations, each relaymay carry as many auxiliary switches as needed. In Figures 6 and 7, athree element auxiliary switch H5 is provided for operating the biasingcircuits which provide for fading to give quiet operation during theshift from one channel to another as discussed in connection with switch56, Figure l. A second auxiliary switch H6 serves to energize the powersupply contactor, and light a signal lamp if desired, as shown at 5!, 52and iii! in Figure l. A third set of auxiliary contacts indicated at ii! may be arranged to function in cooperation with the latch H8, Figure6, providing means for opening the control circuit of the relay after itis latched closed, as indicated at 55, Figure 1, when such anarrangement is considered desirable. Other arrangements of contacts forother purposes may, of course, be provided as required. It will beevident that the construction shown provides great flexibility in theswitching airrangements which may be carried out. A great variety ofcontact opening and closing arrangements, with or without interveningmay be assembled along the lines indicated.

Relays which are to be held closed after receiving a closing impulse maybe provided with latches as illustrated at H8, Figures 6, '7 and 8. Thelatter shows also the trip mechanism com,- prising electromagnet I26,armature I2! and linkage 122 interconnecting the armature m and trip barH9. Linkage $22 may take a variety of forms. As shown in Figure 9 itcomprises a link and bell crank so arranged that bar H8 is momentarilylifted to trip the latches whenever the trip coil I20 is energized. BarH9 is then allowed to drop again even though the relay is stillenergized. This permits any relay receiving an impulse to be closed andlatched, while previously closed relays are released.

Figures 10 and 11 indicate arrangements wherw by, contacts, as I23, forhandling power circuits may be applied to the relays. If certain of therelays are to perform household functions such as lighting the furnaceor operating an appliance, such construction may also be appliedthereto. Such power contacts may be used also with any of the tuningrelays to close the power circuit in place of using a separate contactortherefor. This construction may be used also to make a power circuitcontactor from standard relay parts. Such a contactor may he providedwith interlock contacts similar to contacts H5, and

latch, similar to H8, if desired.

An electrical interlocking and latching system may be used in place ofthe mechanical latches illustrated by H8 and release bar H9 if desired.It will be apparent that a great variety of constructions may be appliedto relays and tuning means of the type described.

Figures 13 and 14 outline arrangements for employing relays, as IE4,similar to those widely used in telephone systems. Each set of contacts,as I25, may have a small separate magnet, as IE8, or the contacts may bearranged two sets to each magnet with suitable shields between contactswhen necessary. Tuning capacitors, as I27, or other circuit elements maybe grouped in association with the relays. An alternative arrangementfor a tuning capacitor is shown at I28. This has worm nut [29, and wormI36 arranged for Vernier adjustment and compact mounting.

Figure 15 shows a superheterodyne type of receiver having three circuitsI3I, I32 and 533 whose tuning is varied in order to select variouschannels. These circuits are radio frequency input circuit i3I,frequency changer input and oscillator input I 33. The circuits may betuned by adjustable capacitors which are connected by relay control asindicated and as described in detail with reference to numerals 32,33-3li, 3E; etc. of Figure 1. Electrical control, latching andinterlocking may be provided as indicated and discussed in connectionwith Figure 1.

Figure 16 indicates diagrammatically, further circuit arrangements whichmay be used in the combination there indicated or in othercon1binations. The first three tubes I I35? and E35 constitute the radioamplifier, frequency changer and oscillator of a superheterodynereceiver suit" able for both short and long wave reception. For shortwave reception. 2. wide range doublet antenna, or other suitable waveinterceptor is connected through a suitable short wave circuit, as I31,to tube HM. Short wave frequency changer and oscillator circuits fortubes I 35 and 13 3 indicated at I38 and I33. For long wave reception,the antenna becomes a T type of aerial feeding long wave input circuitshit for tube I3 3. Circuit MI provides long wave input for tube andcircuit I42 for the oscillator I36. Additional input circuits adapted towhatever radio or wire line channels are to be used may be added andconnected into the systems as required by suitable relays. Tube I43serves the multiple purpose intermediate frequency amplifier forsuperheterodyne reception, tuned radio frequency amplifier for highquality local reception, and carrier amplifier for wire line carrierreception. A sharply tuned intermediate frequency input transformer isindicated at I44 and a band pass transformer for high quality receptionat M5. hese may be tuned for the same or for different intermediatefrequencies and additional transformers may be provided for additionalcharacteristics if desired. Circuit MB indicates a sharply tuned in putcircuit for use with a tuned radio frequency channel, either withseparate aerial or with the same aerial as shown, wherein a suitableautotransformer I ll is employed. The circuit MS may be a broadly tunedband pass input circuit for tuned radio frequency operation. CircuitsI4? and I48, and others when desired may be constructed in accordancewith my copending application 741,139, filed August 23, N34, or in anyother suitable manner. This applies also to circuits I 49 and used forapplying wire line carrier signals to tube I43 from line ISUA. Anysuitable coupling means and input system may be used. Additionalamplifiers succeeding stage I 43 may be provided as required, followedby suitable governor, compensator, demodulator and audio stages. Theseneed not be discussed in detail here as it will be evident from theforegoing illustrative examples that practically any desired combinationof circuits may be brought into play through suitable arrangements.

Figure 1? shows an example of relay control circuits utilizing a controlclock in which the hour hand serves for both the timing and circuitrouting functions. The hour hand I 5I makes successive contact with thetime busses, as I2, and these in turn route the circuit throughinterconnectors, as I3, to the station busses I to I0 inclusive. Therelay coils indicated at I52 may be of a type held closed by continuouscurrent thercthrough eliminating the latches if desired, and the powersupply circuits may be energized by a contactor 53 in the common returncircuit of all relays. A reject button I54 and relay I55 are indicatedto turn elf the set by shunting the power supply relay coil 56. Thereject button i5 5 opens a circuit shunting the operating coil I5! ofthe reject relay, E55, causing the latter to close and cut off the powersupply by shunting coil A. resistor i58 supplies holding potential to55? after the reject button again closes. Reject relay 555 openswhenever the current is momentarily interrupted, by hour hand I 5!dropping from one contact to another. It closes and cuts 01? the powersupply only when reject button 5 is or nod: at all otier times. thepotential across resistor I58 is insutfficient to close it. Th potentialsufficient however, to hold it closed after being closed by operatingbutton I54. two way switch 259 permits a set of butto a.) ibil, to besubstituted for the clock control. buttons are preferably of the typehaving a mechanical interlock which holds one button closed whilereleasing all others.

It will be evident that circuits having relays operated by impulses, asshown in Figure 1 may be applied to a clock of the type indicated inFigure 17. having only hour hand timing control by providing suitableinterlocks and releases.

Figure 18 shows diagrammatically one form of circuit connectionssuitable for applying the mul-- tiple function control clock of mycopending application, Serial No. 82,495. filed May 29, 1936, to an allwave radio receiver utilizing motors for operating the tuning andswitching mechanism hereof. Outline I6! designates the clock controlunit which may be similar to that shown in Figure 1, or like that ofFigure 1'? or one of the other forms outlined in the application justmentioned. Unit iii! may operate a tuning motor directly or via a set ofrelays as indicated at I52. Each relay shown at H52 operates two sets ofcontacts. One set controls a tuning mechanism I63 by means of a actor 461 and suitable reduction In order to provide for precise tuning, a splitspiral commutator, I55, I55A having a plurality o1 brushes as !66arranged therearound is utilized. The brushes must, of course, bearranged to slide axially the commutator is 1'0- tated so as to remainalways in engagement with the spiral commutator. This commutator may bedriven from an intermediate gear, as Hi1, and may maize severalrevolutions for one revolution of the tuner I63. Connections from thetwo halves of the commutator may be made to a split field I68, MEA ofmotor I64. Additional connections may be made to an armature or otherwinding, I69, combining with winding I68 to rotate the motor in eitherdirection as determined by the commutator. A similar arrangementindicated at I10 may provide for rotating a switch to select a desiredwave band. If the latter feature is omitted, the relays I62 may also beomitted and the'tuner I53, motor I64, commutator I85, etc. connecteddirectly to the control unit I51.

In some installations it may be desirable to provide several remotecontrol stations in addition to the clock and the buttons thereon. Thesimplest form of this comprises one or more sets of push buttonsconnected in parallel with those in the clock unit as shown at "I,Figure 19. Alternative programs may thus be selected without in any wayinterfering with future programs scheduled via the clock. When aparallel connected control such as this is employed, it may beconvenient to operate the volume and tone controls by means of smallsplit field motors as illustrated at I12 and H3, Figure 19. Motor I13may if desired operate a rheostat or other means for changing theresponse of the audio amplifier and also operate variable band passradio frequency circuits, as H in accordance with my copendingapplication S. N. 741,139 of August 23, 1934. In Figure 19, numeral 116outlines the clock unit with its clock and button controls. Tone andvolume controls IT! and I18 may be double throw key switches, normallyopen. A remote control station of which any number may be provided isindicated at I19.

Each remote control station has a bank of control buttons, as "I, a tonecontrol I80 and a volume control I81.

An alternative to the arrangement shown, in

igure 19, is to provide a set of interlocked relays, similar to thoseshown in Figures 2 and 7, for transferring the control from the clockunit to one or more auxiliary control stations. Each station may have amaster button or other means of actuating the relay which transfers thecontrol to that particular station. Details of this suggestivealternative and others need not be discussed here.

It will be apparent to those skilled in the electrical and mechanicalarts that my system possesses great flexibility and that it may takemany forms and be applied to many purposes beyond those chosen forillustration herein. I do not limit myself to the forms shown but claimbroadly as my invention the features of novelty and utility set forth inthe claims appended hereto and to my copending applications to whichreference has been made.

I claim:

1. In combination, a communication receiver comprising a plurality ofcommunication channel selecting means, a plurality of relays foroperating said communication channel selecting means, a source'of energyfor operating said relays, and a control circuit for selectivelydirecting the source of energy to correspondingly selected relays toenergize the same, interlock means for holding closed any one of therelays so selected and operated, means including a magnetically operatedmechanical trip member for releasing the interlock when the new relay isselected and for opening all relays when the control circuit is routedvia an Oil position, a contactor operated with the relays for energizingthe power circuits of the receiver when any communication channel relayis closed and an interlock operating with the relays for reducing theoutput of the receiver during operation of the relays.

2. In combination, a communication receiver comprising a plurality ofchannel selecting means, a plurality of relays for operating saidchannel selecting means, a source of energy for operating said relaysand a control circuit for selectively operating said relays, interlockmeans including a latch for holding closed any one of the relaysselected and operated, means for releasing the interlock when a newrelay is selected and for opening all relays when the control circuit isrouted through an ofi position, a contactor operated with the relays forenergizing the power circuits of the receiver when any channel relay isclosed, and an interlock operating with the relays for reducing theoutput of the receiver during operation of the relays.

3. In combination, a communication receiver comprising a plurality ofchannel selecting means, a plurality of relays for operating saidchannel selecting means, a source of energy for operating said relays,means for energizing a selected relay for operating a correspondingchannel selecting means, interlock means for holding closed any one ofthe relays so selected and operated, means common to all of said relaysfor releasing the interlock when a new relay is selected and for openingall relays when the control circuit is routed through an off position,with said interlock means acting immediately, a contactor operated withthe relays for energizing the power circuit of the receiver when anychannel relay is closed, and an interlock operating with the relays forreducing the gain of the receiver during operation of the relays.

4. A radio receiver tuning system including a plurality of electricaltuning means for connection to the tunable stages of a radio receivercircuit, a plurality of relay units corresponding in number to saidtuning means for selectively connecting said tuning means into thereceiver circuit, each of said relay units including a plurality ofswitches, movable means common to all of said switches and operativelyconnected therewith, an electromagnet unit including an armatureconnected with said movable means, interlock means for mechanicallylocking said armature in closed position, a single trip meansoperatively common to all of said relay units acting on said interlockmeans for opening all closed armatures, means for closing a powercircuit in the radio receiver when .any relay unit is closed and meansacting directly on at least one tuning stage in the receiver circuit forreducing the gain in such stage when any relay unit is opening orclosing.

HAROLD F. ELLIOTT.

